Vegetable Storage Solutions

Aspiration system assumes that vegetables are stored in containers in framed storehouses with the use of suction fans. The system is suitable for potatoes. beets, onions sand garlic. It allows for automating the process of storage control and monitoring humidity level, and can be supplied with heating and cooling systems depending on the type of produce and storage period.

Outside, parallel to the outer wall, a storage room wall with vertical openings is built, behind which the air preparation chamber is located. The chamber is equipped with high-pressure fans. These fans suck the waste air from the passages between the containers through the wall openings or discharge the waste air through the intake valves outside; they can also mix the waste air with the fresh air and let it back into storage. The air temperature is maintained with intake and emission valves.

In the storage, there are markings along the wall along where the containers should be placed. The space between each container should be 50cm. They are put into a pile 6-7 meters high. Above and opposite the abutting end wall, the passages between the containers are covered with metal-clad aspiration covers.

The ventilation system is fundamental and is used for drying, curing, decreasing and maintaining the temperature of produce. A refrigeration system is used at high temperatures or when the produce temperature needs to be decreased in a short period of time. 

Aspiration system - ensures a high degree of produce safekeeping with moderate time inputs for startup.  

The slotted-wall storage technique is used only for the container storage of vegetables and is one of today’s most effective technologies. In a storage, there is an air-ventilation chamber separated by a wall where equipment such as fans, intake and emission valves, servomotors, control equipment and sensors is located. For the slotted wall storage technique, storage rooms are built as high as a deck with a space of 1.5-2 meters from the outer wall of the building. Behind the wall, there is an air-ventilation chamber where equipment such as fans, intake and emission valves, servomotors, control equipment and sensors is located.

In a wall, horizontal holes are made at the height of the false bottom. Their width should be equal to the width of a container. The air flows into the storage through these holes, passing through the containers that are densely packed against the wall. In the air-ventilation chamber itself, a false ceiling is arranged parallel to the floor at a distance of 2m. High-pressure fans are mounted into the false ceiling. They move the air from top to bottom and then it flows through horizontal doors into the storage. Above the fans on the outer wall inside the air-ventilation chamber, there are plenum valves through which fresh air flows into the storage. Waste air is removed through emission valves, which are located a bit higher on the same wall. Intake and emission valves usually have the same size and operate simultaneously.

Fresh air flows into the storage through the plenum valves, passes through the fans, and is delivered through the slots in the wall to the containers. Under pressure, the air is forced through the produce. The outgoing air is considered to be waste air and is naturally removed from the storage through the intake valves. The functioning of fans and valves is managed by a special controller and is based on the readings of high-accuracy sensors for temperature, humidity and CO2.

The main airflow goes from the bottom upwards; therefore, the produce at the bottom is better ventilated than at the top. The number of containers that can be ventilated is relatively low: 8-10 containers. Therefore, the length of the storage, as well as the length of the air-ventilation chamber, should be no less than 14-15m.

Pressure system is another a type of container storage for framed storehouses. Their width is a multiple of 4 and can be: 12m, 16m, 20m or 24m. The length of a storage can amount to 30m. However, the longer the storage, the worse the ventilation of all produce. The optimal length is considered to be 24m

Like in other storage technologies, along the wall of the storage there is an air-ventilation chamber (1.5-2m in width) where equipment such as fans, intake and emission valves, servomotors, control equipment and sensors is located. The wall height between the air-ventilation chamber and storage room should be equal to the height of the container decks. Vertical holes (0.4-0.5m) are made in this wall at 80% of its height. Containers with produce are placed on either side of the holes. In the passage formed by the containers, air of the required temperature and moisture flows through the holes. Self-deploying airtubes (airbags) are mounted at the top and opposite end of the corridor so as to force the air to flow through the containers.

Fresh air passes into the storage through plenum valves; it flows from the bottom up through fans installed in the false ceiling of the air-ventilation chamber at a height of 2m and is directed into the passages from the containers. Once the air has been removed, it is considered to be waste air and is naturally removed from the storage through the intake valves. The functioning of fans and valves is managed by a special controller and is based on the readings of high-accuracy sensors for temperature, humidity and CO2. With the help of the airbags, the pressure system provides a more intensive airflow through the produce containers. In all other aspects, the pressure system is similar to the aspiration system. The difference in cost between the two systems is explained by the airbags, which are more expensive than aspiration covers. That said, the pressure system provides a higher quality of vegetable storage.

Every Air technology makes the air circulate through produce containers by creating pressure with the use of fans in a specially-organized stack of containers that are hermetically sealed with pneumatic sleeves. It also replaces excessive levels of carbon dioxide (CO2) and the other byproducts of produce respiration with fresh air so that produced can be evenly ventilated with slight temperature changes.

This storage technology is one of the most advanced found on today’s market.

The technology is based on the proper selection of equipment and its precise arrangement in a storage. Depending on the duration of crop storage, a ventilation, refrigeration or humidification system is used.

The Every Air ventilation system is fundamental and is used for drying, curing, decreasing and maintaining the temperature of produce. A refrigeration system is used when storing at high outer temperatures (in April, May, June) or when the temperature of produce has to be decreased in a short period of time like during crop harvest or while putting produce into storage.

The principle of ventilation arrangement.

Inside the storage, parallel to the inner wall, a wall with vertical openings is erected through which the air gets pressured. Along the openings, containers in hermetically-sealed stacks are lined up in a certain order. Two adjacent rows of containers form a long high passage that gets covered with special airbags at the top and at the abutting end. In this way, they from a closed tube opposite the opening from which the air is pressured.

By pressurizing the air between the rows of containers, fans create pressurized zones there. In this way, air flows through the containers and ventilates the produce. The required storage parameters are maintained with an automatic control system for ventilation, humidification, refrigeration and heating.

Is a quick-build system of container storage for potatoes, carrots, cabbage and beets. This system can be built in either framed or arched storage buildings. The operation of the system is provided by the fans and cooling equipment, which can be mounted on the wall or floor and which is responsible for the entire technical process - from air preparation to its delivery into the storage. Depending on the configuration, the system can include heating and cooling elements, a control valve, a high-pressure fan and an air-ducting system for better airflow. Cold air descends between the containers and is then heated. Waste air is either removed through the emission valves or mixed with fresh cold outside air and brought into the fan unit.

The fan units are made from aluminum profiles. The plenum valve, along with the heating cable, is intended to provide reliable operation at low temperature conditions. The devices are supplied with axial blowers with an average air output of 75 000m3/h. This system is less functional than other container storage systems. At the same time, it is faster and easier to erect. Plus, it is less expensive than more complex systems. This system is often used in small storages or if cold air from the outside is used for cooling produce in the winter, which helps to save on electricity. In order to maintain the required produce humidity, we recommend using the Dragon-M system along with humidifiers.

Underfloor ducts provide air circulation through produce with the help of underfloor air ducts, create uniform temperature and moisture throughout the produce and displace excessive levels of carbon dioxide and the other byproducts generated when vegetables breathe the fresh air. Bulk storage (storing in bulk on the floor of a storage) is one of the most common types of storage in Russia.

The choice of this type of storage is determined by such advantages as:

• Efficient use of storage capacity
• Optimal ventilation and produce drying
• Even temperature maintenance, wooden containers are not needed for this type of storage.

Bulk storage is suitable for such types of vegetables as potatoes, onions, beets. It is also sometimes used, though less frequently, for cabbage and carrots. The ventilation system consists of a load-bearing wall (air-ventilation chamber), the walls of the vegetable storage building and underfloor air ducts. The fresh air flows through the intake valves on the load-bearing wall into a mixing chamber where it mixes with the recirculated air from the storage, obtains the required temperature and humidity levels, and is delivered to the bulk of produce through the underfloor air ducts. The temperature and humidity of the incoming air can be regulated with the use of the recycle valves, humidifiers, heaters and coolers. Forced-air fans can be installed either directly in each underfloor duct or in the hollow floor of the air-preparation chamber. In arched hangars, fans are installed in a specific-capacity grouping at the abutting end of the hangar.

The prepared air is delivered into underfloor cement air ducts with the help of high-pressure fans through the main level pipe.

Depending on storage mode, when the air goes through a pile, it ventilates, cools or dries the produce. If needed, a particular duct can be closed off; for example, if some of the produce in storage has already been shipped, or if a high volume of air needs to be supplied to just-stored produce that has recently been damp. Forced by the high-pressure fans, waste air is removed though the open exhaust valves, or is mixed with the fresh incoming air through the recycle valves. The cycle repeats.

In order to prevent the formation of condensation in a vegetable storage, special fans are suspended at specific intervals (some of which are equipped with heating elements).

When using perforated air-duct technology, the ventilation system provides for air circulation through produce piles with the aid of floor-mounted ducts, creates uniform temperature and moisture throughout the produce and displaces excessive levels of carbon dioxide and the other byproducts generated when vegetables breathe the fresh air. Storing produce in bulk on the floor of the facility is one of the most common storage methods in Russia. The popularity of opting for this storage method is explained by its many advantages, such as: efficient use of storage capacity, optimal ventilation and drying throughout the mass of produce, even temperature maintenance and lack of necessity for wooden containers. This type of storage is the most common on the industrial scale. Bulk storage is perfect for potatoes, onions and beets. The ventilation system consists of a load-bearing wall (air-ventilation chamber), the walls of the vegetable storage building and floor-mounted air ducts. The fresh air flows through the intake valves on the load-bearing wall into a mixing chamber where it mixes with the recirculated air from the storage, obtains the required temperature and humidity levels, and is delivered to the bulk of produce through the floor-mounted air ducts.

The ventilation system is fundamental and is used for drying, curing, decreasing and maintaining the temperature of produce.

The temperature and humidity of the incoming air can be regulated with the use of the recycle valves, humidifiers, heaters and coolers, which are also located in the storage. Forced-air fans can be installed either directly in each floor duct or on the hollow floor in the air-preparation chamber. In arched hangars, fans are installed in a specific-capacity grouping at the abutting end of the hangar. The prepared air is delivered into the zinc-plated floor-mounted air ducts with the help of high-pressure forced-air fans through the main level ducts. Depending on storage mode, when the air goes through a pile, it ventilates, cools or dries the produce. If needed, a particular duct can be closed off; for example, if some of the produce in storage has already been shipped, or if a high volume of air needs to be supplied to just-stored produce that has recently been damp.

Forced by the high-pressure fans, waste air is removed though the open exhaust valves, or is mixed with the fresh incoming air through the recycle valves. The cycle repeats.

A combination ventilation system provides for air circulation through produce containers and replaces excessive levels of carbon dioxide and the other byproducts of produce respiration with the outside air. The combination system is the result of combining of an air cooler with plenum valves. As a result, additional fans are not necessary. As a rule, the combination system is used for small storage capacities.

In storage rooms where refrigerating equipment is needed, a ventilation system that delivers and removes fresh air should be installed. In winter when the temperature is lower than the storage temperature, the system uses cold air for cooling and maintaining the temperature of produce without refrigeration equipment. A refrigeration system is used when storing at high outer temperatures (in April, May, June) or when the temperature of produce has to be decreased in a short period of time like during crop harvest or while putting produce into storage. Artificial air cooling in a storage using a refrigeration system is designed in such a way so as to avoid impacting produce quality and minimize produce crusting and drying.

The required storage parameters are maintained with an automatic control system which was specially designed for vegetable storages. The information can be automatically sent from a controller to a PC or smartphone with an option for remotely monitoring and regulating storage parameters.

The principle of ventilation arrangement

The air combination chamber is located between the outer wall of the building and the air cooler. Air cooler fans provide for air circulation. If cold air from the outside is needed, the plenum valve automatically ajars at a certain angle.

If cold air from the outside is needed, the plenum valve automatically ajars at a certain angle.

The plenum valve blocks the flow of recirculated air from the chamber, thereby providing for the mixing of recirculated air and outside air until the required temperature is reached and excluding freezing. Valves for air removal are also installed in the chamber. Under excess pressure, the warm air is removed from the chamber.

The required storage parameters are maintained with an automatic control system for ventilation, humidification, refrigeration and heating.

The opening of valves is regulated with an electric drive, which changes the opening angle depending on the temperature.

If beets are stored in piles, it is impossible to avoid natural loss. Aside from the loss of sucrose, there is also a possibility of the loss of produce because of bacteria and mold. The use of a forced blowing system and the freezing of beets with the natural cold from fans significantly decreases culling rates. Forced blowing is one of the most efficient ways of decreasing the temperature in piles. It is used when the temperature in piles is 3°C higher than the air temperature.

In a beet pile, field air circuits are placed either on a surface or in the soil. The side-by-side configuration of ventilation is the most common. Air circuits are located at a distance from one another, at roughly 1.5m of the pile height. The volume of air required for ventilation is calculated based on 30-60 m3/h per 1t of beets.

Forced blowing is applied in the warm autumn period, mainly at night. In order to avoid the partial freezing of root crops, it is recommended to stop ventilating if the outside temperature drops below 0°С.

Also, in order to avoid beet withering when forced blowing is applied, it is recommended to humidify the air that is being delivered by fans. Water consumption per one axial fan is 40-50kg/h. This helps to decrease the temperature in the piles more intensively and maintain the optimal level of air humidity for beets (90-94%).

In areas where winters are always cold, it is recommended to freeze beets with natural cold. At the same time, fans provide piles with freezing air from the outside over the course of several days. Beets are frozen until their temperature reaches -12/-15°C; that said, their roots freeze up. To avoid thawing, piles of frozen beets should be covered. Frozen beets can be stored until the end of May with virtually no losses.